Web roll control and method

Abstract

A web roll (A) is positioned on a winding apparatus which includes a belt (B). An electric drive motor (C) drives the belt (B) roll (A) during winding and unwinding of the web. An ultrasonic signaling device (D) directs a signal downwardly towards the web roll and receives a return signal indicative of the size of the web roll for controlling the operation of the electric drive motor which rotates the web roll in a clockwise or counterclockwise direction.

What is claimed is: 
     
       1. Apparatus for unwinding a web roll comprising: a control device for positioning a web roll transversely upon a looped drive belt for winding and unwinding a web from said web roll thereby varying the size of said web roll;   an electric motor driving said looped drive belt during winding and unwinding of said web roll;   a trough in said looped drive belt supporting said web roll during winding and unwinding without restraint upon the web roll causing said web roll to rock back and forth in a longitudinal direction in the trough;   an ultrasonic transducer carried above and directed downwardly toward said web roll sending a signal and receiving a return signal indicative of the size of said web roll while said roll is rocking back and forth changing its position upon said belt; and   signaling means actuated by said ultrasonic transducer when said web roll reaches a predetermined size producing a change of operation in said electric motor while said web roll is rocking back and forth.   
     
     
       2. The structure set forth in claim 1 wherein said control device includes web delivery means for alternately winding or unwinding said web roll, and control means for selecting rotation of said web roller in a clockwise or counterclockwise direction. 
     
     
       3. The method of winding and unwinding a web roll comprising the steps of: positioning a web roll transversely upon a looped drive belt for winding and unwinding a web from said roll thereby varying the size of the web roll;   driving said looped drive belt during winding and unwinding the web;   supporting said web roll upon a trough in a substantially horizontal portion of said looped drive belt during winding and unwinding without restraint upon the ends of said web roll causing said web roll to rock back and forth in a longitudinal direction in the trough;   directing an ultrasonic signal downwardly toward said web roll and receiving a return signal controlled by the diameter of said web roll while said roll is rocking back and forth changing its position upon said belt; and   generating an output signal to said electric motor in response to said return signal from said web roll while rocking back and forth changing its position upon said belt, producing a change of speed in said electric motor directly proportional to said diameter of said web roll.